Spine

Spine builds a central spine with reorderable FK, IK and Reverse FK layers, optional Tweak controls and a deformation joint chain.

Configuration

In Module Manager, choose Spine in Module Bank, or its instance in Scene Modules.

Spine · CONFIGURATION · Poseidon theme. Tweak enabled.

Reference	Purpose
1 · Side	Central module: C only, without mirroring.
2 · Output Color	Deformation joint color. On a built instance, changes apply immediately.
3 · Topology	Placers sets the number of placement handles; Outputs, the number of deformation outputs and joints. Defaults: 3 placers, 5 outputs.
4 · Layers	Enable layers and drag FK, IK or Reverse FK to change their order. Tweak stays last. COUNT sets the number of controls; SHAPE and COLOR set their appearance.

Count, activation and order changes require Rebuild on an existing instance. Shape and color changes apply immediately.

Minimums: 2 placers and 3 outputs. The output count must also cover the controller count of each active FK or Reverse FK chain. At least one FK, IK or Reverse FK layer must remain active.

Placement

Place the first placer at the spine base, the last at its tip, and the intermediate placers along the desired curve. The placement curve follows their translations live; placer rotation and scale are locked.

Controls

Controller	Role
FK	Chain from base to tip. 3 controls by default, 2 minimum.
IK	Three fixed controls: Base, Mid and Tip, for the spine ends and center.
Reverse FK	Chain from tip to base. 3 controls by default, 2 minimum.
Tweak	Local adjustments composed last. Disabled by default; adjustable count, 1 minimum, initially matching the outputs.
Options	Dedicated control for layer visibility and volume compensation.

The default order is FK → IK → Reverse FK. Layers compose together; this is not an FK/IK switch. The preview below includes Tweak.

Module Preview

Spine · Module Preview · Tweak enabled.

Options

Setting	Effect
FK Visibility, IK Visibility, Reverse FK Visibility, Tweak Visibility	Show each layer’s controls without disabling its deformation. Initially, only the first layer is visible.
Volume Weight	Blends volume compensation from 0 to 1; default 1. Keyable.
Volume Power	Sets the compensation strength during stretching or compression, from 0 to 2; default 0.5.

Compensation acts across the spine, strongest around the middle and fading to zero at both ends.

Inputs and outputs

Ports are central (C) and expose the driver and reference matrix channels.

Direction	Port	Role
Input	base	Incoming motion at the spine base.
Output	base	First deformation output.
Output	tip	Last deformation output.
Output	rev_pelvis	Pelvis motion from Reverse FK, isolated from the other layers. Without Reverse FK, follows the base frame.
Outputs	deformation_01…	Outputs distributed along the spine; their count follows Outputs.